The Information Commissioner of Canada has found evidence of "systemic interference" with access to information requests by three Conservative staff members, and suggests bringing in the police.
But Public Works Minister Diane Finley, who oversees the department where the interference occurred before her time, won't be sending the matter to the Mounties.
Her office linked the findings against the three staffers to a related case that did not result in criminal charges.
"They chose not to pursue the matter further and the minister agrees with the RCMP," said spokeswoman Alyson Queen.
Cases date back to 2009
Suzanne Legault delivered her second report Thursday following an investigation into cases that date back to 2009 in the office of cabinet minister Christian Paradis, who held the Public Works portfolio at the time.
She had already found against one staff member, Sebastien Togneri, in a previous investigation that was sparked by a Canadian Press access-to-information request.
Togneri resigned in 2010 after The Canadian Press reported he had been involved in other cases of meddling.
Colleagues Marc Toupin and Jillian Andrews also turned up in emails tabled with a parliamentary committee.
Staffers 'inserted themselves' into access process
Legault looked at five additional cases, finding Togneri interfered in all of them, Toupin in one and Andrews in one.
The records ranged from the sensitive asbestos file, to U.S. President Barack Obama's visit to Canada.
Andrews currently works as a senior aide in the office of Environment Minister Leona Aglukkaq.
It is not clear if Toupin is still in the government's employ.
"These staffers inserted themselves in various ways into a process that was designed to be carried out in an objective manner by public servants," Legault wrote in her report.
"Consequently, the rights conferred under the Act were compromised."
Department initially refused to hand over records
Legault also described how she had to resort to using her powers to order the production of documents, after the department refused to divulge records held within the minister's office.
Five months later, they turned over the files.
Ministerial records are not covered by the Access to Information Act, but the Supreme Court has found that they can be reviewed if they deal with departmental matters.
It turned out that those records -- emails between political staffers -- did deal specifically with departmental business.
They helped to form Legault's finding against Toupin.
Evidence a possible offence committed
In an interview, Legault explained why Canadians should care about the investigation.
"The reason why we have an objective, non-partisan process in the Access to Information Act is to make sure that the Act is a key instrument in holding our governments to account," she said.
"It cannot and must not be that political staffers or politicians thwart the intent of the Act and prevent Canadians from holding governments to account when they're entitled to disclosure of information."
Legault says there is evidence a possible offence has been committed.
The act forbids anyone to "direct, propose, counsel or cause any person" to conceal a record, with a maximum penalty of $10,000 and two years in jail.
No one has yet been convicted under the section.
But Legault again noted her dismay that she cannot refer matters to the Attorney General of Canada for investigation herself.
In the case of Togneri, former Public Works Minister Rona Ambrose referred the matter to the Mounties, but no charges were ever laid.
The department also undertook to make changes to how it handles access to information after the Togneri report, which Legault said were "laudable initiatives."
She made a pointed reference to the responsibility of ministers and top bureaucrats to make sure the access to information system is protected.
She said that a culture of "pleasing the minister's office" had been fostered among public servants.
"The integrity and neutrality of the access system depends on strong leadership from the top," she wrote.
"Ministers and senior managers must ensure their employees know their responsibilities with regard to access to information, and the limitations on their roles."